Such a method and such an apparatus are known from patent application DE 10 2008 054 005 A1. FIG. 1 of that patent shows a plan view of a vehicle negotiating a bend. The vehicle has adaptive headlamps that are pivoted through a pivot angle with respect to the longitudinal axis of the vehicle. The procedure for adjusting the pivot angle and for determining the pivot angle at which the adaptive headlamps are pivoted is as follows: first, a so-called look-ahead distance is determined. In principle, the look-ahead distance can be arbitrarily established. The look-ahead distance on vehicles with headlamps installed at a height of 65 cm is usually 65 m. To obtain optimum illumination of the road when negotiating a bend or driving straight, the look-ahead distance is usefully set to the so-called reference beam range of the headlamps and the selected headlamp light distribution. The reference beam range results from statutory provisions under which the low beam must have a 1-% slope with respect to the longitudinal axis of the vehicle. The reference beam range for the low beam designates the location of the so-called knuckle.
The knuckle is the point that results from a projection of an intersection of a horizontal portion of a cut-off line of the headlamp and an ascending branch of the cut-off line of the headlamp in a plane on the road surface, wherein the plane in which the intersection lies is in front of the vehicle and perpendicular to the longitudinal axis of the vehicle. The plane can, for example, be a test surface for light from the headlamp, as used when setting headlamps (see “Motor Vehicle Lighting Technology and Screen Washing”, ISBN: 3-7782-2039-X, p 35, FIGS. 15 and 16).
Once the look-ahead distance is determined, in the method disclosed in patent application DE 10 2008 054 005 A1, the point in the look-ahead distance from the vehicle is determined that lies on the centerline of the highway in the course of a highway that is to be traversed. Once this point is established, the direction of the point from the vehicle is determined. The angle between the calculated direction of the point on the centerline of the highway and the longitudinal axis of the vehicle is the desired pivot angle to which the headlamps are pivoted when negotiating a bend. After the headlamps have pivoted, the so-called knuckle lies in the middle of the highway.
According to the aforementioned method, when driving on the right, especially for left-hand turns, the headlamps swivel so extremely that the areas of the headlamps that are intended to illuminate only the right-hand side of the highway when driving in a straight line (and that are to the right of the so-called knuckle) also cast light on the left side of the highway. Thus there is a risk of oncoming traffic being dazzled. In right-hand bends, on the other hand, the knuckle of the cut-off line is partially pivoted over the right edge of the highway, resulting in a reduced illumination of the right-hand side of the highway.